1. Technical Field
The invention relates to methods and materials for diagnosing unstable angina as well as for determining an individual""s predisposition to have an unstable angina condition.
2. Background Information
Coronary artery disease is characterized by long periods of clinical stability with few or no symptoms. In addition, classical pathologic studies have demonstrated that the disease is commonly far advanced anatomically before any symptoms are reported (Blumgart HL et al., Am. Heart Journal, 19:1 (1940)). An additional characteristic of coronary artery disease is a propensity to an abrupt, sometimes catastrophic, change in a previous stable or silent clinical course leading to a variety of acute coronary syndromes (Fuster V et al., N. Engl. J. Med. 326:310-318 (1992)). The fundamental mechanism responsible for provoking such abrupt changes in clinical status of patients with coronary artery disease is unresolved.
The invention involves methods and materials for diagnosing an unstable angina condition in a patient. Specifically, the invention provides methods and materials for classifying an angina condition as either stable or unstable. In addition, the invention provides methods and materials for determining an individual""s predisposition to have a stable or unstable angina condition.
The invention is based on the discovery that the frequency of cytokine-producing cells within a patient suffering from an angina condition can be used to help a clinician determine whether that condition is stable or unstable. Specifically, the invention involves determining the frequency of cytokine-producing cells in a patient and determining whether that frequency corresponds to the frequencies found in 1) healthy individuals, 2) stable angina patients, or 3) unstable angina patients. For example, unstable angina patients tend to have an elevated frequency of both CD4+ and CD8+ T cells that produce INF-xcex3.
The invention also is based on the discovery that the frequency of CD4+/CD28null cells within a patient suffering from an angina condition can be used to help a clinician determine whether that condition is stable or unstable. Specifically, the invention involves determining the frequency of CD4+/CD28null cells in a patient and determining whether that frequency corresponds to the frequencies found in 1) healthy individuals, 2) stable angina patients, or 3) unstable angina patients. For example, unstable angina patients tend to have an elevated frequency of CD4+/CD28null cells.
Determining whether an angina condition is stable or unstable is important for determining the proper course of treatment. Briefly, an unstable angina condition is much more serious than a stable angina condition and requires much more intense clinical attention. Thus, if clinicians can determine the stable or unstable nature of angina condition, patient""s suffering from an angina condition can be diagnosed and treated appropriately.
In addition, the invention is based on the discovery that the frequency of cytokine-producing cells as well as the frequency of CD4+/CD28null cells in a individual can be used to determine the individual""s predisposition to have a stable or unstable angina condition. Specifically, the invention involves determining the frequency of cytokine-producing cells and/or the frequency of CD4+/CD28null cells in an individual and determining whether those frequencies correspond to the frequencies found in stable angina patients or unstable angina patients.
Determining whether an individual is predisposed to have a stable or unstable angina condition can help individuals prepare for and prophylactically treat potentially life-threatening disease. For example, once individuals learn of their predisposition they can change their diet and daily activities such that the chance of developing an unstable angina condition is reduced.
In general, the invention features a method for diagnosing an angina condition in a patient. This method involves stimulating lymphocytes (e.g., CD4+ or CD8+ cells) from the patient, determining the frequency of cytokine-producing cells among the lymphocytes, comparing the frequency of cytokine-producing cells to a reference frequency to obtain information about the patient""s angina condition, and classifying the angina condition as stable or unstable based on the information. A phorbol ester (e.g., phorbol myristate acetate) or a calcium ionophore (e.g., ionomycin) can be used to stimulate the lymphocytes. The frequency of cytokine-producing cells can be the percent of CD4+ cells producing INF-xcex3, the percent of CD8+ cells producing INF-xcex3, the percent of CD4+ cells producing IL-2, or the percent of CD4+ cells producing IL-4. The reference frequency can be the median frequency of cytokine-producing cells derived from a population (e.g., a population of unstable angina patients, stable angina patients, or healthy individuals). For example, the median frequency of cytokine-producing cells can be the median percent of CD4+ cells producing INF-xcex3 derived from a population, the median percent of CD8+ cells producing INF-xcex3 derived from a population, the median percent of CD4+ cells producing IL-2 derived from a population, or the median percent of CD4+ cells producing IL-4 derived from a population.
In another embodiment, the invention features a method for determining the predisposition of an individual to have a stable or unstable angina condition. This method involves stimulating lymphocytes from the individual, determining the frequency of cytokine-producing cells among the lymphocytes, comparing the frequency of cytokine-producing cells to a reference frequency to obtain information about the individual, and classifying the individual as being predisposed to have a stable or unstable angina condition based on the information.
The invention also features a method for diagnosing an angina condition in a patient. This method comprises determining the frequency of CD4+/CD28null cells in the patient, comparing the frequency of CD4+/CD28null cells to a reference frequency to obtain information about the angina condition, and classifying the angina condition as stable or unstable based on the information. The frequency of CD4+/CD28null cells can be the percent of CD4+ cells that are CD28 negative. The reference frequency can be derived from the CD4+/CD28null cell frequencies from a population (e.g., a population of unstable angina patients, stable angina patients, or healthy individuals). In addition, the reference frequency can be the percent of CD4+ cells that are CD28 negative. For example, the reference frequency can be greater than about 2.0 percent or less than about 2.0 percent.
In another embodiment, the invention features a method for determining the predisposition of an individual to have a stable or unstable angina condition. This method involves determining the frequency of CD4+/CD28null cells in the individual, comparing the frequency of CD4+/CD28null cells to a reference frequency to obtain information about the individual, and classifying the individual as being predisposed to have a stable or unstable angina condition based on the information.
In another aspect, the invention features a kit for providing diagnostic information about an angina condition in a patient. The kit contains a binding pair member and a reference chart. The binding pair member has a specific binding affinity for a cytokine such that the frequency of cells producing the cytokine from the patient is determinable. The reference chart contains information about cytokine-producing cell frequencies such that an indication of the stable or unstable nature of the angina condition is determinable based on the frequency of cells producing the cytokine from the patient.
In another embodiment, the invention features a kit for determining the predisposition of an individual to have a stable or unstable angina condition. The kit contains a binding pair member and a reference chart. The binding pair member has a specific binding affinity for a cytokine such that the frequency of cells producing the cytokine from the individual is determinable. The reference chart contains information about cytokine-producing cell frequencies such that an indication of the predisposition is determinable based on the frequency of cells producing the cytokine from the individual.
The invention also features a kit for providing diagnostic information about an angina condition in a patient. The kit contains a binding pair member and a reference chart. The binding pair member has a specific binding affinity for a CD4+/CD28null cell marker such that the frequency of CD4+/CD28null cells in the patient is determinable. The reference chart contains information about CD4+/CD28null cell frequencies such that an indication of the stable or unstable nature of the angina condition is determinable based on the frequency of CD4+/CD28null cells in the patient.
In another embodiment, the invention features a kit for determining the predisposition of an individual to have a stable or unstable angina condition. The kit contains a binding pair member and a reference chart. The binding pair member has a specific binding affinity for a CD4+/CD28null cell marker such that the frequency of CD4+/CD28null cells in the individual is determinable. The reference chart contains information about CD4+/CD28null cell frequencies such that an indication of the predisposition is determinable based on the frequency of CD4+/CD28null cells in the individual.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.